In gear manufacturing machines, a worker typically exchanges a machining tool manually. However, because various devices, parts, and the like are provided in a gear manufacturing machine, the worker must take into account interference with nearby devices when exchanging the tool. Furthermore, the machining tool must be attached to the gear manufacturing machine correctly to prevent problems with cutting accuracy from arising in the gear manufacturing machine. In other words, the worker must stay safe and pay attention when exchanging the machining tool. In particular, workers unaccustomed to the process of exchanging the machining tool may slip and drop the machining tool, and thus such workers must take extra care to stay safe and pay attention when exchanging the machining tool. Furthermore, when exchanging a machining tool that has been lengthened or the like in order to extend the lifespan of the tool and is thus heavy, the worker must be strong and take greater care to stay safe, and this places a greater burden on the worker.
Thus in gear manufacturing machines, automating the exchange of the machining tool can be considered as a way to lighten the burden on the worker. A hobbing machine including a hob changer disclosed in Patent Document 1 can be given as an example of a gear manufacturing machine including an automatic tool changer capable of automatically exchanging a machining tool in this manner.